pambayer: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/pambayer - from package: netpbm-progs

You may install the required package with command yum install {package}

Error in other languages:
pambayer: bevel nie gevind nie
pambayer: comandă negăsită
pambayer: comando não encontrado
pambayer: commande introuvable
pambayer: command not found
pambayer: käsku ei ole
pambayer: không tìm thấy lệnh
pambayer: komanda nerasta
pambayer: Kommando nicht gefunden.
pambayer: kommandot finns inte
pambayer: komut yok
pambayer: nie znaleziono polecenia
pambayer: níor aimsíodh an t-ordú
pambayer: no se encontró la orden
pambayer: no s'ha trobat l'ordre
pambayer: opdracht niet gevonden
pambayer: parancs nem található
pambayer: perintah tidak ditemukan
pambayer: príkaz nenájdený
pambayer: příkaz nenalezen
pambayer: команда не найдена
pambayer: командата не е открита
pambayer: 命令找不到
pambayer: コマンドが見つかりません